1. Field of the Invention
This invention relates to sequential stepped movement staging devices, and particularly to automated sequential stepped movement devices having six legs of equal length organized in an X-Y-Z orthogonal relationship extending radially from a horizontally fixed central sphere, wherein movement of an underlying work surface is accomplished by stepped rotation of the legs so that the ends of the legs act on an array of upwardly facing dimples in the work surface to walk the work surface from a first position at the beginning of a step to a second position at the end of a step.
2. Description of the Related Art
The typical X-Y axis staging device includes a first lead screw in the X axis and a second lead screw in the Y axis. A first motor drives the X-axis lead screw and a second motor drives the Y-axis lead screw. Each axis usually has an encoder to translate the rotation of the lead screw into an exact position along that axis. Each motor requires drive electronics. Such devices have application in the semiconductor and pharmaceutical industries where a task must be repetitively performed on a large number of identical objects, e.g., applying an etching pattern to a semiconductor wafer, performing a chemical analysis, or combining drugs into a beneficial compound. This type of stepped movement staging device is structurally complex and expensive even when its function is limited to stepping a fixed distance in either or both axes. If the device is required to operate in a vacuum or liquid environment, the equipment becomes much more complex and expensive.
There is therefore a need for a sequential stepped movement staging device that is structurally simpler, less expensive to manufacture, and able to function in severe environments.